In the last several years, moviegoers have grown accustomed to seeing Marvel characters pull off one superheroic feat after another. Iron Man swoops in to rescue 13 hapless souls plummeting to their doom after a fall from Air Force One. High-flying Captain America skips the parachute as he foils insidious plans for a Helicarrier fleet to decimate the planet’s population. Iron Man, Cap, Thor, and the rest of the Avengers band together to save New York from being annihilated by invading alien hordes.

But in the cosmic action romp “Guardians of the Galaxy,” opening Friday, another group of Marvel heroes is vying to record the greatest feat of all: making a blockbuster draw out of a property that’s had a limited profile even among comics fans. Before Marvel’s current run of self-produced screen successes, you’d hear industry speculation that, say, “Iron Man” might struggle because the character wasn’t known to audiences, and lacked the iconic heft of Batman or Spider-Man. Which was a stretch, of course — Iron Man was
a name that registered with the mainstream on some level, even if somewhat confusedly, thanks to triathlons and the old Black Sabbath tune.

“Guardians,” by contrast, is genuinely unfamiliar, the unlikeliest Marvel property to get a big-screen push since “Blade,” in the late ’90s. Back then, Marvel was a bankruptcy-bailout case aspiring to get into the movie game. Now the company is a Disney-owned powerhouse willing to gamble that its brand trumps its secondary characters’ visibility, or lack thereof.

“Guardians” is headlined by Chris Pratt (“Parks and Recreation), as Peter Quill, a.k.a. Star-Lord, a spacefaring thief-turned-good guy with Earth roots and more than a touch of Han Solo roguishness. Aside from maybe “Moneyball,” in which Pratt played Red Sox castoff and A’s reclamation project Scott Hatteberg, he’s never had a gig this unexpected — as befits the movie, really. (Next up: the franchise relaunch “Jurassic World,” due in 2015.) Star-Lord’s scruffy compadres include green-skinned assassin Gamora (Zoe Saldana, swapping her blue “Avatar” avatar for a Margaret Hamilton makeover); brawny, butt-kicking Drax the Destroyer (WWE vet Dave Bautista); and CG creations Rocket, a wisecracking, gun-toting raccoon voiced by Bradley Cooper, and Groot, an anthropomorphic, monosyllabic tree voiced by Vin Diesel.

Never heard of this bunch of self-proclaimed Guardians? Neither had comics readers until just a few years ago. The Guardians of the Galaxy were first introduced by Marvel in 1969, but in a completely different incarnation, one which spent as much time as a guest-starring sidelight as it did in the spotlight. Geeks of a certain age will recall that the group even got loosely folded into the “Avengers” comics for a time. Then, in 2008, Marvel creators repurposed the Guardians moniker, slapping it onto a collection of editorially discarded characters like Star-Lord. They would lend the entire enterprise an increasingly freewheeling tone, the sort you could get away with when you weren’t dealing with Spider-Man and other characters of corporate significance. And why not? Even the name Peter Quill was originally a bit of subversive slang for, um, jerk, as Sean Howe, author of “Marvel Comics: The Untold Story,” notes in an entertaining “Guardians” primer on Vulture.com.

The reconceived team was a good fit for a couple of items highlighted on Marvel’s creative checklist. Marvel Studios president Kevin Feige has spoken passionately about how much the company had wanted to do a big, cosmic epic. Fans were already primed for space action by an “Avengers” end-credits teaser featuring intergalactic baddie Thanos. (The character doesn’t figure into next year’s “Avengers: Age of Ultron,” but he’s a presence in “Guardians,” and Josh Brolin, who tackles the role, has a multi-picture deal with Marvel. Stay tuned for “Avengers 3.”)

Film Frame (c) Marvel 2014

Glenn Close as Nova Prime.

Along with changing up its movie backdrops a bit, Marvel seems intent on trying some tonal change-ups — specifically, by dabbling in action-comedy. Yes, “Iron Man” has Robert Downey Jr., but that’s more like an improv cherry on the franchise’s action sundae. “Guardians” feels shaggier, starting with trailers that sample Blue Swede’s “Hooked on a Feeling” and poke fun at that low profile. (Pratt to funky alien Djimon Hounsou: “[I’m] Star-Lord.” Hounsou: “Who?”) The film is directed and co-written by James Gunn, a fanboy pro whose credits include genre spoofs “Super” and “The Specials.” And as Marvel follows up “Avengers 2” with what it bills as Phase Three of its film slate, we’ll also be seeing Paul Rudd in, yep, “Ant-Man.” That one is being directed by comedy vet Peyton Reed, who signed on after Edgar Wright dropped out.

Along with changing up its movie backdrops a bit, Marvel seems intent on trying some tonal change-ups — specifically, by dabbling in action-comedy.

One rationale for Pratt’s casting reportedly was the prospect that the Guardians and the Avengers could one day meet onscreen. You never know — Tony Stark already hangs with Star-Lord’s crew in the comics. “If . . . this actor is talking to Robert Downey Jr.,” Gunn recently told Entertainment Weekly, “I wanted him to give as good as he got.” By that point, maybe the exchange won’t even have to open with, “Who?”